Stephen A. Lawrence wrote:
Aw, these reports drive me nuts. I'd not read this one, I think. They
have a pump for cooling water, it seems. So when they start up, they
are pumping an estimated 6.47 kg per hour of water. They assume that
this flow rate remains the same. Why?
It's a constant displacement pump. That's what it does.
That's right. They also measured the flow rate by letting the water fill
a 500 ml bottle. You can't repeat that test once it produces steam,
except by sparging, which is another reason I would like to sparge the
steam. (Mainly to capture the enthalpy.)
They should have put the reservoir on a weight scale they way they did
in the first test. (Maybe they did, and did not report that, which would
be unprofessional.)
But anyway, it is not likely the flow rate changed significantly. As you
say, that's what those pumps are for.
This is, as I said, second-rate calorimetry, but still completely
convincing. It would not be as convincing if the heat were not so high,
or if they had not also tested the gadget with liquid state flowing water.
The flow rate (which is *fixed* by the CD pump), times the coolant
temperature rise (scaled by the specific heat, of course), gives the
power carried off by the coolant. They're claiming that the heater
power and power carried off by the coolant match at 60C.
That is correct, and it does. I checked.
- Jed
